I can see where this would be a challenge - it seems clubs change logos just enough to make logo making a never ending saga. The link below leads to the new Baltimore logo.
Orioles change wardrobe -- baltimoresun.com
I also visited the Ebbets Field Flannels web site recently and it appears to be a trove for you to draw on. I've put just two examples below - the 1914 Brooklyn Tip-Tops (FL) and the old New Orleans Pelicans logo:
1914*Brooklyn Tip-Tops*Cap - Ebbets Field Flannels
1942*New Orleans Pelicans*Ballcap - Ebbets Field Flannels
I really appreciate all the quality work you've put into these 'simple cap style' logos and just wanted to show that resources for further logos of very cool teams of the past are available. Wish I had the ability to craft them.
Anyway, thanks.